1. Field of the Invention
The present invention is related to computer telephony communications and more particularly, to providing call completion services between communications devices at different computer telephony interface (CTI) platforms.
2. Background Description
A typical computer telephony interface (CTI) integrates telephony communications with computer data communications, e.g., connecting a public switched telephone network (PSTN) to a local area network (LAN) and/or the Internet. The telecommunications connection point is typically referred to as an endpoint and that endpoint is in what is known as a switched sub-domain in the particular communications network. Normally, the endpoints are monitored by a software application such as what are known as computer supported telecommunications applications (CSTA) that provide application service interfaces for switching, computing and special resource functions. Calls made between endpoints can traverse multiple communications infrastructures, e.g., a session initiation protocol (SIP) in an Internet protocol (IP) based network, a switched circuit network (SCN) or an enterprise private network, such as a private branch exchange (PBX) based network.
As each call traverses between infrastructure endpoints, each CTI may assign a different, unique call identification (ID) attribute to it that the switching function uses to represent a valid call. In CSTA a call ID has the form of: callID (M) Octet String. The maximum length supported by the switching function is provided via the capabilities exchange services. These IDs are created by the switching function and are globally unique among all calls within the switching sub-domain. For example, a call may originate with a 10 digit telephone number (800-555-5421), a CTI to an IP network may assign one CSTA attribute (e.g., mobile@ 10.23.23.244) to identify the call as it traverses the IP network and another CTI may assign another, unique 3 digit ID (e.g., 987) as it exits the IP network at a second endpoint.
So, normally, the CSTA at each endpoint assigns the call linkage attributes to calls traversing between endpoints. Then, the CSTAs tunnel CSTA attributes (call linkage) thru a signaling channel with the call to identify and maintain the identity of events with the call. These attributes correlate events from the monitored endpoints. However, many infrastructure protocols may not support tunneling the call linkage attributes. So, unfortunately, these types of infrastructures have previously been unavailable for use in a CTI platform.
Thus, there is a need for maintaining the identity of events with respective calls in communications infrastructures that do not support call linkage attribute tunneling.